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by howlgarnish 2050 days ago
That would be Hong Kong Kai Tak "Heart Attack" approach: https://youtu.be/NiPyrfEuOeo

There's one particular video (which I can't find right now) which shows an airplane about to land at an angle due to strong crosswinds, then essentially hovering in place for a moment so it can reorient correctly before touching down. I'm still not sure how that's physically possible with a jetliner (ground effect?).

5 comments

If you refer to this video [1] the fact that the plane approaches "at an angle" is called "crabbing" and the "reorientation" at the very end is called "de-crabbing" [2], this looks very dramatic from the point of view of external onlookers, but it is actually more comfortable for passengers because it doesn't involve uncoordinated flying (in other words the plane stays "flat" instead of banking towards the incoming wind) and for this reason it is the preferred technique for airliners (as opposed to the other crosswind landing technique, which is called side slipping and involves lowering a wing into the wind). You can see a comparison of the two techniques here [3] (look at "Figure 1" and you will easily see the difference). You are correct that ground effect is quite visible in that clip.

[1] https://www.youtube.com/watch?v=OtnL4KYVtDE

[2] actually in the clip this happens twice, crab, de-crab, then crab again then de-crab once more on touchdown. The Kai Tak checkerboard approach, even without crosswind, was an incredibly difficult approach and in this case the pilot had to perform a couple of corrections.

[3] http://www.flaps2approach.com/journal/2014/6/17/crosswind-la...

This happens fairly regularly (in my experience) at Leeds and Bradford airport too. https://www.youtube.com/watch?v=LAljM7CaY10
Thanks for the explanation, this video is even better than the one I was thinking of!
That video is the difference between "I bet I could land an airplane in an emergency, if someone talked me through it" and "apparently pilots actually learn something in pilot school".
Flying into Kai Tak was a fantastic experience, especially at night. Looking into the buildings rushing past each side and watching them get relatively higher as the plane descended made it really weird. Plus the last few seconds when all you could see was water outside made it feel like you were about to land on the sea, followed by the sudden bump, thump of ground contact.
I think you might be looking for https://youtu.be/bKqO6gdJIz8 (at about 0:33 in)

Shows a 747 banking at an incredible angle (though I feel like that hovering thing may just be an optical illusion)

Based on parent's comment (which mentions crosswind) I think it would look more like this (i.e. a crab landing) https://www.youtube.com/watch?v=OtnL4KYVtDE
Crazy when you think that plane probably weighs around 250 tons at that point.
Probably an optical illusion? I don't think a plane can hover over a fixed point, unless the headwinds are strong hurricane force or something.

With very strong headwind, a normal plane could theoretically land vertically, or even backwards. I wouldn't recommend it though.

Can’t do it with a 747, but with a lightweight bush plane and a steady wind you can. https://youtu.be/QFllgHbjnlU
Yes - "hovering" in a fixed-wing is very much possible, and even desirable for STOL landings (very popular & competitive in the Alaskan bush scene).

It's still very much an observer-effect illusion however. The observer considers the speed in terms of groundspeed, the physics consider the speed in terms of airspeed. If the difference between the two values exceeds the stall speed of the airframe, the effect is sustainable.

I'm sure it's not at all the same, and in particular, they're using larger planes like the 747, but it reminds me of the approach to San Diego (minus the turn).